On Fri, Feb 03, 2012 at 10:34:20PM +0100, Reindl Harald wrote: > > > Am 03.02.2012 20:58, schrieb Stephen Harris: > > On Fri, Feb 03, 2012 at 08:04:31PM +0100, Reindl Harald wrote: > >> does not change that it is a dmaned good idea this days > >> to make matching A/PTR/HELO and it is EASY to do this > > > > A & PTR, yes. HELO, no. It's not even possible to do HELO matching PTR > > when NAT gets in the way. > > WHAT has NAT to do with this? > > my mailserver has intern 10.0.0.x, external 91.118.73.x > my internal DNS has the PTR/A for the NAt address > external DNS have the PTR/A for the public idea > > what in the world let you think that NAT does change anything? If your mail server talks to machine with IP address 1.2.3.4 then should it say HELO with the 10 address name or the 91 address name? The mail server doesn't know what IP address will be presented to the remote machine, so it can't pick the correct name for the HELO. This is why I agree that A/PTR values should match, but there's no way for the HELO value to match. -- rgds Stephen